Elastic helical gearing.



K- ALQMST. ELASTIC HELIGM GEARING. APFLICAUON FILED ram/3.191s.

Patented Dec; 28,1915.

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Inventor": Kr-J Luist ruin snare rarnirr KARL anems'r, or sonnnnomnr, NEW YORK.

ELASTIC HELICAL GEARING.

1,165,828. Specification of L e Patent Patented Dec. 28, 119115.

. Original application filed January 17, 1814, Serial No. 812,812.- Divided'and this application filed May 3,

1915. Serial no. 25,513.

To all whom it may concern: complete'circle. In helical gearing, though Be it known that I, KARL AL UIsT, a subt e contact between the teethis a line conject of the King of Sweden, residin at Schetact, this line is, as is well understood, with nectady, county of Schenectady, tate of regard to practical value for carrying load,

New York, have invented-certain new and so short as to form only a point contact 60 useful A Improvements, in Elastic Helical (being the intersection" of the line of con- Gearing, of which the following is'a specifi-- tact and the pitch line) because the tooth cation. surface. outside the pitch line is subject to The present application'is a division of rapid Wear, due to-the sliding action of the my application Serial No. 812,812, filedteeth, and the driving pressure is concen- 65-- January 17, 1914. trated on a point moving along the pitch line y invention relates'particularly to clas as the'gears revolve. There is evidentl tic helical spurgea'ring of the type which one such pressure point for each tooth crosscomprises a plurality of elastic or flexible ing the driving line, This pressure point plates or laminations rigidly mounted on .may'also beidefined as the intersection be- 70 ance space between each two plates near the The principle of the Invention may also be periphery. The face of the gear is provided stated in another form by saying that each With helically out teeth which are free to individual disk should carry the load at any yield laterallyby a slight amount under time only on one (theoretical) pressure 75 e pressure of the teeth of the cooperating point, being'a. point common to the drivin gear. This yielding of the gear teeth is due line and the pitch line, or that, in other to the fact that the metal plates are elastic Words, the number of pitch line pressure and also tothe fact that each plate at its poln s in a gear built up according to this periphery is separated from the other by a ln entlon 1S, equal to the number of disks. 80 mall p he required axial vvldth, as described I have found that when a gear is built up above, Will be given by the equation from a pack of comparatively thin laminab:p/tan a certain respects under conditions approxi- Where f a i 85 m y we of ordinary sh teeth and birdumferential itchunder similar disadvanta es. althou h the and p p teeth are cut helically across the pack of lamin'ations. The essential characteristic of ii ip teth Wltlh axls' the helical type, the load concentration on In practice 1t is advisable to add approxi- 90.

the pitch line, is practically missing, and mately 10% to the theoretical width given straight gearing. carried just at the end of a tooth where it 40 I have found by experiments that in order is weakest. This'will, of course, add to the 9,5 to obtain the special advantages of the heli length of the gear, but on account of the f gearing with the multiple disk relative increase in strength .of the teeth construction, while retaining the advantage 'thus obtained a smaller pitch may be used of flexibility or elasticity and avoiding cerwhich more than nakes up for the additain difficulties present in connection with tional length by increasing the wearing sur- 100 the running of this type ofgearing, it is imace, as now there will be more teeth crossing [portant that the teeth of each disk should t 1e driving line per unit length. The comaxis, This-Width is determined by what may certain size of gear.

be called the principle of continuous pitch It will be understood that, if the width of line; i. e.,'each disk shouldhave such a width the disk is increased substantially beyond that the projection on a plane at right anthe dimensions given, the load for a given glcs to the axis of the gear of all the pitch disk will be carried alternately on one and lines on the tocth'ofthe disk will form' a twojpressure points thus giving unequal 110 surface load. If the width were increased so that two points were theoretically always carrying the load; 0., if the width were doubled. this would, at first sight, seem to be an acceptable condition, but apart from other disadvantages it will be found that as a rule only one point carries the load of the disk, due to the deflection, and a larger pitch would have to be chosen for reasons of strength, involving loss in wearing surface, and in general practice such a gear will be considerably inferior to the one pressure point type described, though it may be used for reasons of economy in special cases where large disks are necessary.

I have in the attached drawing shown diagrammatic views of a gear made according to this invention. Figure 1 shows a plan of a gear built up from a number of disks (the clearance between the rims not being shown), and Fig. 2 gives a. developed plan of a portion of the rim of one disk on a larger scale, the teeth being shown in section on the pitch line, anddllustrates theequation already given for the width.

Referring to Fig. 1, 3 indicates a shaft carrying a helical gear wheel formed 0 the plates or laminations at. In Fig. 2 the theoretical width is represented by 7),; additional width is c The spaces defined by 1', and c, will carry the load at the same time. The practical width is thus b,+c ::b,. The line ccl represents the driving line and 72 and a are respectively circumferential pitch and helical angle of the teeth. A pressure point, as previously described, is the intersection between the line 0-(Z.and a pitch line, and it will be understoodfrom the figures that when the disks revolve (the driving line being stationary), such a pressure point will move along a pitch line as this line is crossing the line c- -cl, and each disk will only have one pressure point on the main or middle portion of its face or width. for transmitting the load at but will have two pressure points (on parts e, and 6,) while the load is shifted from one tooth to the next.

in such a position with reference to the driving line that the two pressure point.

period is just commencing,

one pressure point being at f and the other about to start Gopies of this patent may be obtained for any time,-

Fig. 2 shows the teeth five cents each, by addressing the at g, the teeth moving in the direction indicated by the arrow.

In accordance with the provisions of the patent statutes, 1. have described the principle of operation of myinvention, together with the apparatus which represent the best embodiment thereof;- but I desire to have it understood that the'apparatus shown is only illustrative, and that the invention can be carried out by other means.

\Vhat I claim as by Letters Patent of the United States, 1s,

1. A gear comprising a plurality of laterally flexible helical toothed members arranged side by side so as to be capable of lateral deflection, the axial Width of the teeth of each member being substantially such as to give continuously a single pitch line contact.

2. A. helical gear comprising a plurality of elastic plates clamped together at their central portions and free to yield laterally under tooth pressure, the teeth of each plate having an axial width substantially equal to the circumferential pitch of the teeth divided by the tangent of'the angle which the teeth make with the axis of the gear.

3. A helical gear comprising a plurality of elasticplates clamped together at their central portions and free to yield laterally under tooth pressure, the axial width of each plate being such 'hat the teeth out thereon will have a width slightly greater than the circumferential pitch of the teeth divided by thetangent of the angle which the teeth inakewith'the axis of the gear I now'consider to new and desire to secure i. A helical gear comprising a pluralityflg of elastic disks firmly clamped together at be equal to the number of disks the greatest.

part of the time. I p In witness whereof, I have hereunto set my hand.

KARL ALQUIST.

Commissioner of Eatents,

Washington, 1). G.

so as to be capable 

